View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Springer - Publisher Connector Aquat Ecol (2011) 45:75–87 DOI 10.1007/s10452-010-9333-9 Abiotic factors affecting the development of Ulva sp. (Ulvophyceae; Chlorophyta) in freshwater ecosystems Beata Messyasz • Andrzej Rybak Received: 26 January 2010 / Accepted: 7 July 2010 / Published online: 20 July 2010 Ó The Author(s) 2010. This article is published with open access at Springerlink.com Abstract The influence of physicochemical factors with stable and deeper water, the surface area of the on the development of Ulva species with distromatic mats was larger. Both phosphate and nitrite concen- tubular morphology was studied in three streams trations were positively correlated with an increase in located in Poznan, Poland. The study evaluated key the number of thalli in the mats and the thalli length. environmental factors that may influence the coloni- sation and growth of Ulva populations in freshwater Keywords Ulva Á Chlorophyta Á Macroalgae mats Á systems. In total, nine environmental parameters were PCA Á Ecology Á Nutrients included: temperature, water depth, pH, oxygen (O2), ? - ammonium (NH4 ), nitrate (NO3 ), phosphate 3- (PO4 ), sodium chloride (NaCl) and total iron Introduction (Fe). Morphometric features of thalli (length and width, percentage of furcated and young thalli) and The cosmopolitan genus Ulva (Fish and Fish 1989; surface area of free-floating mats formed by the Fletcher 1996; Callow et al. 1997;Ba¨ck et al. 2000; freshwater populations of Ulva were compared at all Gabrielson et al. 2000; Graham and Wilcox 2000; sites. Principal components analysis indicated the Blomster et al. 2002; Hayden et al. 2003; Leskinen most important factors influencing Ulva development et al. 2004) is mostly found in marine and brackish were sodium chloride concentrations and water waters (Kirchhoff and Pflugmacher 2002; Lee 1999; depth. Two other key chemical factors affecting the Romano et al. 2003) and estuaries (Ba¨ck et al. 2000; freshwater form of Ulva were phosphate and nitrite McAvoy and Klug 2005). It can also be present in concentrations. High concentrations of sodium chlo- freshwaters, often in ecosystems located far inland on ride inhibited the development of Ulva, leading to a continents and islands that are not in contact with salt lower number of thalli in the Ulva mats. At the sites waters. During the 20th century, such freshwater Ulva populations have been recorded in eight coun- tries, including Great Britain (Whitton and Dalpra 1968), the United States (Taft 1964; Reinke 1981), Handling editor: Piet Spaak. the Czech Republic (Maresˇ 2009), Japan (Ichihara et al. 2009), Pakistan (Leghari et al. 2000), New B. Messyasz (&) Á A. Rybak Zealand (Williams 1993) and Poland (Messyasz and Department of Hydrobiology, Institute of Environmental Rybak 2009). Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska Str. 89, 61-614 Poznan, Poland Thirteen species of Ulva have been reported from e-mail: [email protected] the Polish Baltic coastline (Plin´ski et al. 1982; Plin´ski 123 76 Aquat Ecol (2011) 45:75–87 and Florczyk 1984). Typically, marine Ulva species using examples from three streams in Poland. An have also been observed in several freshwater systems additional concern was to evaluate the impact on in Poland (Go¨ppert and Cohn 1850; Kozłowski 1890; Ulva species in freshwater ecosystems, associated Raciborski 1910; Wysocka 1952; Piotrowska 1961; with anthropogenic sodium chloride pollution and Plin´ski 1971; Sitkowska 1999; Messyasz and Rybak nutrient (N and P) enrichment. 2009). Between 1849 and 2007, five species and one subspecies of Ulva were observed at 58 inland sites in Poland (Messyasz and Rybak 2009). These occurred Materials and methods as either single or large concentrations of thalli in various freshwater ecosystems, mostly lakes, but also Study area in small rivers, streams and ponds. Other sites included peat pits, clay pits and stream basins. The The study sites containing Ulva were located in most common species at these inland Polish sites three *0.5-m deep steams in the south-eastern area included Ulva intestinalis (34 sites), U. flexuosa of Poznan´, Poland (Fig. 1). Two sites containing Ulva (10 sites), U. prolifera (5 sites) and U. compressa were in the Michało´wka stream (52°2002000N, (4 sites). Also, the rarest Ulva species in Polish 17°0204400E and 52°2002100N, 17°0204500E) and one in freshwaters, U. paradoxa, has been observed at only the Dworski Ro´w stream (52°2102800N, 17°0203000E). 2 sites, while the subspecies U. flexuosa subsp. The sites in Michało´wka and Dworski Ro´w were pilifera has been seen at 3 locations. located 541 m from each other. Another location Young Ulva have a thallus that remains either containing these macroalgae was in the S´wia˛tnica attached to a substrate or they can develop unat- stream (52°2103900N, 17°0204200E), which is 4.5 km tached, as drifting individuals or as aggregations of from the other two sites. All sites containing Ulva were free-floating mats (Bliding 1963, 1968; Starmach in the vicinity of a motorway. The Michało´wka sites 1972). Freshwater forms of Ulva appear only as (hereinafter ‘‘M1’’and ‘‘M2’’)were 34 m and 19 m from monostromatic tubular thalli (e.g. Ulva intestinalis the motorway, respectively. The third site in Dworski and Ulva compressa). So far, Ulva with distromatic Ro´w (hereinafter ‘‘DR’’) was 425 m from the motorway, frondose thalli has not been reported in freshwater and the fourth one in S´wia˛tnica (hereinafter ‘‘S’’) ecosystems (Messyasz and Rybak 2009). Mature was located 246 m from the motorway. plants of freshwater Ulva can have one of the two types of thalli surface architecture. One has an intestinally undulating thallus with a smooth surface, Chemical analysis and the other is curly bubbled with a strongly corrugated and often highly furcated thallus (Marczek The physicochemical parameters of waters from the 1954). It has been frequently observed that a few four sites containing Ulva were analysed when the Ulva species form freely floating thallus mats macroalgae thalli were present, i.e., from August (Fletcher 1996; Callow et al. 1997; Blomster et al. until October, 2007. Water temperature, pH and 2002). Their appearance in a marine littoral zone has oxygen levels were measured using Elmetron been related to the nutrient enrichment of littoral CX-401 and CPC-501 protocols with this analysis, waters (Wallentinus 1979; Sfriso and Marconimi repeated weekly. Additionally, changes in water 1997; Raffaelli et al. 1989; Martins et al. 2001; depth, thickness of bottom sediments and shading Zbikowski_ et al. 2005). of the sites by vascular plants (immersed and floating) This paper’s objective is to provide additional were monitored. Water samples (500 mL) were information to previous ecological studies of fresh- collected for chemical analyses and preserved with water Ulva populations in Poland. Detailed ecolog- 0.5 ml of chloroform. These samples were then ical studies of parameters that influence the stored in refrigerators at 4°C, with chemical analyses occurrence of Ulva species in freshwaters need to performed using standard methods for a Hach DR be investigated. Therefore, the goal of this work was 2010 spectrophotometer. Concentrations were deter- to determine the influence of the colonisation and mined for the following variables: ammonium, growth of Ulva populations in freshwater ecosystems nitrate, phosphate, sodium chloride and iron. 123 Aquat Ecol (2011) 45:75–87 77 Fig. 1 Location of the sampling sites of freshwater Ulva populations in the Wielkopolska region (Central Europe, Poland, Poznan City). 1 motorway, 2 streams, 3 water channels, 4 roads, 5 railway, 6 forests, 7 built-up areas, 8 meadows Both the percentage of water surface area covered and morphometric features of thalli defined using by Ulva thalli and the density of Ulva thalli per m-2 Pearson’s linear correlation coefficient including r2 of surface water were evaluated in the field. The ratio. A PCA (principal components analysis) method lengths and widths of thalli taken from each site were was used to compare the diversity of physicochemical also measured. The morphometrical measurements environmental parameters and then to determine were repeated ex situ on material preserved with relationships to the Ulva populations. formalin (4% concentration). Macroalgae mats were analysed to determine the number of furcated thalli and the presence of young and mature plants. Results Statistical analysis Physicochemical profiles of the study sites STATISTICA 7.0 and CANOCO 6.2. software were During the study period (July–October 2007), water used for the statistical analysis of the collected data. temperature and pH values were similar for all sites. The correlation between physicochemical parameters The highest water temperature was at S because of 123 78 Aquat Ecol (2011) 45:75–87 Table 1 Average values of physicochemical factors of water for the examined sites Parameter Units M1 M2 DR S Temperature (8C) 14.77 (2.56) 15.09 (2.68) 14.75 (2.73) 15.72 (2.48) pH – 8.16 (0.67) 8.11 (0.64) 8.04 (0.52) 7.97 (0.70) Depth of water (cm) 50.12 (19.36) 44.00 (22.76) 48.68 (9.60) 16.25 (3.07) -1 O2 (mg L ) 2.26 (1.29) 2.12 (1.47) 0.52 (0.20) 4.00 (0.78) ? -1 N-NH4 (mg L ) 1.34 (1.19) 1.44 (1.18) 0.90 (0.82) 0.31 (0.58) - -1 N-NO3 (mg L ) 0.64 (0.36) 0.70 (0.37) 0.40 (0.35) 0.05 (0.02) 3- -1 P-PO4 (mg L ) 0.71 (0.15) 0.74 (0.19) 0.19 (0.11) 0.02 (0.01) NaCl (mg L-1) 544.97 (38.33) 549.25 (26.77) 651.35 (81.30) 697.51 (78.87) Total Fe (mg L-1) 0.29 (0.24) 0.31 (0.18) 1.18 (0.62) 0.04 (0.03) Data are means (SD); n = 30; M1, M2, DR and S—sites the shallow water level of the watercourse (average Similar values in the results of these sites may be temperature of 15.72°C at an average depth of associated with their close proximity to each other in 16.25 cm).